Betwixt The Sheets: The History of Sex, Scandal & Society - History of Kissing: Why do we lock lips?

Episode Date: August 11, 2023

A good old smooch. It’s something that we do on a daily basis in one form or another (if we’re lucky), and yet have you ever stopped and wondered why we do it? Wonder no more. On today��s Betwixt the Sheets we’re joined by Emmy award-winning scientist and author of The Science of Kissing, Sheril Kirshenbaum, to find out answers to questions such as, why has the letter X has come to mean a kiss? What role has the colour of our lips played in our evolution? And why do men prefer kissing with more saliva? This episode was edited and produced by Stuart Beckwith. The senior producer was Charlotte Long. If you're enjoying Betwixt please vote for us at the British Podcast Awards here: https://www.britishpodcastawards.com/voting. It would mean the world to us!Discover the past on History Hit with ad-free original podcasts and documentaries released weekly presented by world renowned historians like Kate Lister, Dan Snow, Suzannah Lipscomb, Lucy Worsley, Mary Beard and more.Get 50% off your first 3 months with code BETWIXT. Download the app on your smart TV or in the app store or sign up at historyhit.com/subscribe.Hosted on Acast. See acast.com/privacy for more information. Hosted on Acast. See acast.com/privacy for more information.

Do you want even more shocking and scandalous history? Like why the ancient Greek statues had such small manhoods? Or what went on behind closed doors in the Georgian era? We'll sign up to History Hit, where you can see me discover the scandalous side of history, as well as hundreds of hours of original documentaries, plus new releases every week, covering everything from prehistoric Scotland to the Treaty of Versailles.

Sign up to join me in locations around the world and explore the past. Just visit historyhit.com forward slash subscribe. Lovely for Twixters, it's me, Kate Lister. I'm so glad that we get to do this again. Thank you for dropping by. This is the part of the show where we just make sure that absolutely everything that follows is okay with you. This is your fair do's warning.

This is an adult podcast spoken by adults to other adults about adulty things on a range of adult subjects, and you should be an adult too. And now that we're all on the same page, if you persist in listening to this and if you happen to get offended, well, tough tits, you were warned. A smooch, a snognecking, I've heard it called, a peck, a canoodle. Whatever it is that you like to call it, a kiss has many names and can be many, many different things. It can be affectionate, it can be sexy, it can be caring, it can be maternal, paternal, loving or just plain old friendly. and of course they are very context dependent.

There are people that you kiss and there are people that it's just, you just don't kiss your doctor when you first go in to greet them. You don't kiss your boss when you go in for a meeting. These are just the rules of kissing. But when you really boil it down, it is quite a strange act anyway, isn't it? You just push your face really close into somebody and pucker up and get a bit of dribble on them.

Why do we do it? I know that we think kissing is just, an innately human thing, but have we always done it? Why do we do it? And what does it mean to different people? If our all mate Sigmund Freud is to be believed, then the reason that we kiss is because we are eternally in search of the comfort our mother's first gave us. But he would say that, wouldn't he? That was his whole thing, blame mummy. But, but maybe he was on to something. Maybe. Or maybe there's another reason that humans love to express themselves through this soft, fleshy bit on the front of our faces.

Pooker up, betwixters, we are delving in to explore the history of the kiss. What do you look for a man? Oh, money, of course. You're supposed to rise when an adult speaks to you. I make perfect coppents of whatever my boss needs by just turning a knob and pushing the fun of it. Yes, social courtesy does make a difference. Goodness, my beautiful time. Goodness has nothing to do with it, Derry.

And welcome back to Betwixt the Sheets, the history of sex scandal in society. With me, Kate Lister. What makes for a good kiss? Hmm. This can be dependent on many, many things, of course, who it's with, what you're feeling at the time, if it's consensual. And perhaps most importantly,

what was the last thing that your kisser ate? It's something that seems to have always been part of the human experience. But if you ever stop to wonder, really wonder, Why do we kiss? Why do we kiss each other? What drives us to lock lips? And why have some societies throughout history attempted to ban kissing? Today we are joined by Cheryl Kirshenbaum, author of The Science of Kissing, to really get Betwixt the Sheets and find out more. But before we get into that episode, I have a little favour to ask you. If you are enjoying Betwixt, we would really love it if you would vote for us for the listeners choice award at the British podcast awards.

It only takes a couple of seconds and I promise it would make a huge difference to us. Think of it as a favour, one in the bank and that you can ask me for a favour should our paths ever cross. If you follow the link in the show notes, you can click, give us a vote and honestly, we might even get it this year. We were so close last year and it's just, oh, come on, we can do it this time, but Twixtas. I know we can. Right.

Let's get back to kissing. And welcome to Betwicks the sheets. It's only Cheryl Kirshenbaum. How are you doing? I am so excited to be talking to you today, Kate. That's how I'm doing. We're talking about the history of kissing and this, this is fascinating because I hadn't really thought about it. I just assumed people have always kissed. It turns out there's a whole history and biological, evolutionary theory. around this one simple act that I had never even thought of before. Well, and you're not alone, because for the most part, science has largely ignored kissing as well. And I think it is because it's so obvious.

We all do it, but it's almost, I don't want to say perfunctory, because kissing isn't perfunctory, it's anything but. But it's so commonplace. It's like we pour money into studying things like how dung beetles survive, and we ignore this super significant behavior. that our species does. So more reasons that we should be talking about it. Right. What brought you to this subject? What was your journey to, I need to research why human beings kiss? Great question because it's not something I intended to do, but I am a scientist and a science writer. And so I became

noted, well, I don't want to say I became noted for it. That sounds too important. But people started to expect that my work would take topics that are very familiar to us and kind of break it down scientifically. And so around 2008, I wrote, I got just a 400 word piece for new scientist magazine on the Science of Kissing to coordinate with Valentine's Day. And I thought that would just be a one-off, but it did that thing where articles go viral. And suddenly these scientists at this big scientific meeting wanted me to organize a whole symposium on the science of kissing. And it was, I was getting so many questions and emails following up on this. I just thought, you know, there's a big story here.

And the more I dug in, the more I realized that there were these seemingly disparate pieces of research, like the endocrinologists had done just a little bit, and the neuroscientist had done just a little bit. And the anthropologists sort of were thinking about it. But no one was putting this together in a story. And what a wonderful opportunity to do that and talk about science and talk about how it's relevant to our lives. And of course, there's a lot of history there too. And now you're the kissing scientist. Now that that's your whole thing. It's definitely something that's fun to be noted for. I feel like it's a topic that doesn't seem

to be waning in popularity at all. No. No. And I love that as well. When you get a scientific subject and then you look into what all the different scientists have been saying about it and they're all saying things that are quite different from one another. And you think, can all these things be true at once? Can like what the evolutionary biologists be saying be the same? as what the geneticists and the psychiatrists are saying. It's a massive subject. Like, how did you start to wrestle it into one coherent narrative? Well, what I actually loved was it wasn't so much they were saying different things, but they were looking through different lenses. So there was actually a lot of interest in what the other folks were doing, right? So you had these brain scientists,

and I actually got to go into a neuroscience lab at New York University, and we conducted our own experiment, not kissing each other, but just looking at visual images of kisses. And they were going, you know, we're seeing these changes in the brain when we look at images of kissing, but have you talked to what the endocrinologists are saying? Like, how are the hormones in our bodies changing as we kiss people? And can we tie those two things together and draw any conclusions? And this happened over and over and over. So it was just so cool, because I got to make a lot of introductions for scientists that would never otherwise have a chance to talk to each other. I love that.

This sounds like a really obvious question, but I'm going to go with it. Have humans always kissed each other? Is there like evidence for, I suppose by kissing, I mean, well, actually, no, you're the scientist. How do you define kissing for the purpose of your research? Oh, so much to say there. So first of all, one of the earliest things I learned working on this book was, despite our obsession with pretty much everything else in the animal kingdom and all sorts of human behaviors, there's not even like a taxonomy or a classification of how scientists describe humans kissing.

And, you know, that as an aside for the fact that we haven't spent too much time thinking about it or studying at all. And so, you know, we might talk about kissing as just two people pressing their lips together or pressing their lips on some other part of the body. But really, the descriptions of kissing, it kind of depends what you're talking about because there have been cultures that didn't kiss mouth to mouth. But when you think about, you know, a lot of this was taking place around the world before the advent of toothpaste and mouthwash. That doesn't seem so strange. All that said. So when the book came out, the earliest literary evidence we had for kissing dated back about 3,500 years to India's Vedic Sanskrit texts. However, in the last month or two months, new evidence came from Mesopotamia dating back the first evidence we have to 4,500 years ago.

But here's the thing. We don't know, but we can look all around the animal kingdom, and we see so many similar kissing-like behaviors in other species. Animals kiss each other? Well, we have to be careful. If we want to be put our science hats on, scientists tend to get... No, no, no science hats. I want to know if dogs kiss each other.

I promise I won't make it boring or take the magic out of it. But scientists tend to be... All right, okay, science hat back on. We have to be a little careful when we talk about the emotions of animals, because if we get too into the weeds of saying, oh, they're in love. There's a lot of criticism. We're accused of anthropomorphizing, which means, you know, assuming we understand what that animal's experience might be.

That said, there are so many, I want to call them parallel, similar behaviors all across the animal kingdom. And they all occur for these very socially significant reasons. So we see bonobos, which are a great ape relative. Bonobos have been observed to suck on each other's tongues for 10 minutes straight when they're in coitus and when they're, you know, engaged in, you might call a relationship. And they swap partners all the time. They're a very sexual species.

Maybe you've talked about them on the show before. They're a lot of fun. Chimpanzees, they hug and they touch lips. But we see all these other species, too. Dogs lick us. They like any noun, person, place, or thing. All different socially significant reasons. And so you go on and on and you see this repeated.

I think it's fair to say, and actually this is something Charles Darwin, the father of evolutionary biology talked about, despite that we only have evidence at this point dating back 4,500 years, humans have probably been kissing in some form for as long as we've been on Earth. It just didn't necessarily look like kissing as we would recognize it today on the street as two people press lips together. Because there's lots of different types of kissing. I was just thinking that as you were talking about like dog kisses and kind of like all like my nieces and nephews who I adore, I'll kiss them every time I see them. But that's not the same thing as a bonobo kiss, that would be weird and then the police would be involved.

So like, like, different kisses mean different things, right? Like, you might do the double-cheek French kiss, or, you know, you might blow someone a kiss or kiss your kids, but then you kiss a lover or kiss as a mark of respect, the Pope. They can mean so many different things, right? They really can. And, you know, kissing. We often talk about science and behavior as nature versus nurture. And that's just not right. This is such a wonderful example of nature and nurture complementing each other. So our species, human beings seem to have an instinctive drive to connect through kissing. But the way it looks, the shape it takes, the style it is, is absolutely influenced by what's familiar to us, what we see on billboards and television and streaming channels.

And, you know, this has been going on for a long time, Shakespeare. And so many authors in the past, They spread kissing through people reading about these romantic moments on assuming this should happen in their lives. But what's absolutely wonderful is you can trace kissing's origins back through cultures all over the world. You see it arise and disappear in different places. It might have to do with the spread of disease. It might have to do with an emperor, an ancient Rome deciding he didn't want his subjects to kiss each other this way. It might have done with depressing feminine sexuality. There were people that didn't think women should kiss because it created eroticism in the way.

their minds and that might not be so okay. So it was a bit of a control issue. But you see this happening all around the world and the way that we kiss today, it doesn't just vary by nation. It varies sometimes by zip code. It's what we know and what's familiar to us. And yes, of course, what you said before, there's there's so many different kinds of kisses because we kiss to connect. We kiss because there's all these neurotransmitters and hormones that are influencing the way we feel. And those are not just associated with romantic love, but also comfort, security, all of these positive feelings that we probably experienced in infancy when our parents or loved ones, you know, caressed and kissed us. And even as we breastfed, because lip stimulation gets associated with those positive emotions.

Or bottle fed, just fine too. Wow. If you speak to a psychologist or a Freudianist, I should say, they will tell you that the reason that we kiss is because of breastfeeding, that as infants, we took a lot of nurture and comfort from that act, and then we're kind of still doing it as adults. But they would say that. But if I would say, why do we kiss? Like from a scientific point of view, what purpose does it serve?

What would be your answer to that? Is there an answer to that? There are. Well, there's two ways to answer that question. There's what we call the ultimate reasons, and that would be tracing back evolutionary biology. So why did humans start doing this? And we can talk about the nursing,

behaviors, we can talk about attraction to lips and attraction to that rosy color and why this visual cues are so important. But we can also talk about what we call the proximate reasons. So in our own lives, what did we experience, most of us at least experience early in infancy, even in the womb we're sucking our thumbs that are laying down these neural pathways in us as individuals, making us kind of crave that nurturing, secure feeling of comfort and love. and kind of both of those are equally valid. And Freud talked about kissing as kind of the long-term need to return to the breast. But Desmond Morris, another biologist, had a similar theory,

but he didn't talk of it as something that was lost. Like Freud was always like, we're trying to get back to our mother's breast. Desmond Morris talked about it as just kind of that need to reconnect with the emotions themselves that we had through all of that cuddling and love. Very important. So I would kind of add to that because we can go in a million directions. I get very excited when I talk about science and kissing. One of the aspects of kissing has to do with choosing a romantic partner, of course.

Not all kisses are romantic. But kissing what other behavior puts us that close to another individual to get a reliable, beyond colognes, beyond perfumes, beyond all of those things. When you're pressed up close against another human being, you're getting a reliable sample of their scent, their natural scent. And there's cues involved there. that draw us to someone else, or maybe repel us if we thought things were right

and suddenly everything seems a little bit off. We're not consciously thinking about what those are, but our body is sending us message. It's kind of nature's ultimate litmus test. It's a way to judge, is there a future together? And some of it even has to do with reproduction. Like, is this a person if I go off and mate with, you know, have a baby, will that baby be healthy?

So lots of signals going on in our brains and bodies and a kiss is just the way to put ourselves in close proximity to have that reliable indicator. It's kind of neat. That's very neat. I just remembered now, I read a paper from evolutionary biologists about why humans perform oral sex on each other, because from an evolutionary point of view, it's kind of a weird thing to do. There's like, why are we doing it? And that was the reason they put forward. They said that the reason we're doing it is almost as like a health test, which isn't very romantic when you say it like that, But that was their theory as well.

It might not be the only reason, but that's certainly in the mix. This is what happens when you speak to evolutionary biologists about really, really nice things. The reasons that they come up with, it's always just like, yeah, because you know, you're just a monkey that wants to have sex with your mom. And when you break down why we do the things we do, this was actually some of the stuff I found the most interesting while writing the book. Nothing is universal. So there's a spectrum of opinions.

and we want to account for like generalizing, which is what I'm about to do. But in general, there's been research by psychologists of how men and women view kisses. And of course, they only talk. Most of the research I found only looked at heterosexual like cisgender people. The work that I did incorporated a more diverse sample. But they did find these psychologists, they were at State University of New York at Albany. They found that there are significant differences in general with how men and women describe kissing, why they do it, what they enjoy, what they don't like. The big picture of that

was basically that women tend to describe kissing as a way to figure out if their relationship has a future, if they're compatible with someone, whereas men were far more likely to describe kissing as a means to an end. Like, I'm giving her a kiss, hoping that we exchange other bodily fluids down the line. But when you kind of unpack that, women have... a stronger sense of taste, a stronger sense of smell, and we really truly use kissing for that reason to judge whether we want to pursue more with a person. And so I think we were seeing that play out in the way that they were talking to these psychologists about their interest in kissing altogether. I'll be back with Cheryl after this short break. Hi, I'm Eleanor Yonaga, and I'm thrilled

to be joined Matt Lewis to co-present Gone Medieval from History Hit. Twice a week, every week, we set out to answer the big questions that have vexed people. for centuries. Like, what did the Romans ever do for us? Roads, buildings, walls, churches, houses, manuscripts. Why did Edward I mourn his Queen Eleanor so much? He was very good at making a show for people to see that was going to influence how they would understand him or his campaigns or anything like that. Did Viking hero Ragnar Lothbrook really exist?

Maybe yes, maybe no. The sons who were attributed to him were definitely real people. So join me, Eleanor. Norianaga and me, Matt Lewis, for Gone Medieval from History Hit. Listen and follow on Apple, Spotify, or wherever you get your podcasts. I would use kissing as a benchmark of, like, is this person going to be a good lover? I've never known somebody who's been a bad kisser that they've then gone on to rock my world. It's always just like, if the kissing is bad, like, that's a bad prelude, isn't it?

In my opinion, it's just, if that bit's gone wrong, then I'm not really looking forward to finding out what else there is. I think that's a fair assessment. I think you're onto something there, Kate. Yeah, I think so. Well, you know, maybe I'm wrong. But yeah, if someone's a bad kisser, I think they're going to be bad in the sack. That's my completely unscientific conclusion. The number one complaint from work by psychologists in New York from women was that they did not like too much tongue. They did not like sloppy kissers overall. No, no. Do you know that like when you talk about the bonobos when they just suck on each other's tongues for 10 minutes when they're having sex. I had like bad date flashbacks when you said that. Well, but men often say they do like a lot of

tongue. This is the point where scientists are to speculate, but it's an interesting aside. So men have a little more testosterone in their saliva. And women, while we have testosterone, we're very sensitive to that hormone. So scientists have speculated that when there's a lot of sloppy tongue kissing, men are introducing a little bit extra saliva, so a little bit extra testosterone into their female partner's bodies. And it doesn't happen overnight. This isn't a one-night stand kind of thing. But if that man is repeatedly kissing his partner for weeks and months, it might increase her sexual receptivity and make her more interested in sex. Now, this is speculative, but I think it's a very interesting consideration that could potentially account for why men say

they love these sloppy open-mouth tongue kisses and women are a little bit like not so into it. But like, why does so many women complain that their partners don't go down on them then? That is a fabulous exchange of testosterone. We should get, this should be a public service announcement. Well, now it is. Now it might be. Oh, I love that. That's wild, that it's like a buildup of testosterone.

So they think, yeah, yeah. Well, there's all these absolutely fascinating hormonal aspects to kissing that I think we're not necessarily consciously aware of. but they're pushing us and pulling us in these teeny tiny invisible ways, helping us figure out who we want to be with. While we're on the subject of oral sex, talk to me about the color red, because I've definitely heard that. I've heard that the flushed red of the lips is reminiscent of the vulva,

or is that just pop psychology, internet, blah, blah, blah. It is not. So Desmond Morris, the same person I mentioned earlier, he describes the lips as a genital echo. So think about that when we're plumping up our lips. and doing all this thing, we're actually creating this mimic of what our labia might be doing. But it goes back. So when I was working on the book, I spoke to a neuroscientist called V.S. Ramachandran,

who was thinking about evolution. And we were talking about how our ancestors long before our humans were humans, but our primate ancestors really had to find ripe fruit for sustenance. And I won't go into all the details. But over time, we started to recognize the collar red. Red often indicated something was ready to eat and that could help us survive. And so, and we see in cultures all over the world, as they develop languages, black and white were often the first two colors that had names for night and day. And then red was often the third most important color, third color named and that probably had to do with food.

So fast forward quite a bit. Red became an indicator of sustenance, but it also began to be emphasized on parts of the anatomy. Because of blood, right? That could bring other pleasures. So, yeah, so we see in bonobos, in all sorts of baboons, when the females are in estrus, when they're ready to mate and reproduce, their bottoms turn bright red. I had one primate scientist say with the species she studied, it looks like they're sitting on a bright red ball. It becomes engorged and inflamed. And in our species, there's a version of this too.

And when girls go through puberty, they have more estrogen, their lips get a bit fuller, a bit bigger. It's very attractive. We see for thousands of years dating at least 5,000 years back in time, women are highlighting their lips with wines and dyes and different tints that they found in nature and elsewhere. And that's something that we continue today. And today we do that beasting effect. We do the irritants on our lips. We inject ourselves. We even do implants. People do Gortex implants in their lips. I don't think that's quite so popular. And supposedly certain people can feel them when they kiss. But it's something that we continue to enhance. And I think most of us aren't thinking that we're creating a genital echo, but in fact, that seems to be an aspect of it,

at least. That'd be a hell of a makeup marketing campaign, isn't it? This is our new genital echo line of lipstick. That's always in the back of my head when I see different stories about celebrities and lips, and I think, I wonder if they know. I bet they don't know, but really they should know. It's a good dinner party conversation. Let's talk about good kissing,

Because it's fascinating the reasons why humans might do this, but good kissing is an art form. And I know that there's a chapter on it in the Kama Sutra. Do they give tips for being a good kisser? The Kama Sutra says a lot about this. And we have other historical texts that do as well. But based on at least everything that I've been reading, a good kiss, yes, has to do with, you know, technique.

You don't want to be licking someone's whole face and all of those things. But a lot of it has to do. do with kind of intuitively understanding your partner and recognizing what they might want because we all have different sexual preferences and interests and things that feel good and so so much of it happens on an individual basis but that said we also know things like stress and kissing don't mix so even if it's like stress kissing yeah the absolute right person for us in the wrong context right like you're surrounded by your grandparents and you're in a synagogue or church or somewhere and you're just like you're not feeling it.

That kiss isn't going to be good pretty much no matter what else is happening because you're going to be so conscious of all. You're going to be sweating. You're going to be your, you know, there's all these changes you want in your body, but then cortisol, the stress hormone, it's going to just put a damper on all of that good stuff. So, you know, the good kiss really has to do with the right partner at the right time and the right moment. I love that.

I mean, that's true. It's so context dependent. isn't it? You mean, you've got to really, a lot of it is about timing, I think, with these things. And what I love, and I hope that this doesn't take kind of the magic and romance out of it, because I think it just adds to it. But we describe, we kiss someone and we feel butterflies or we feel, you know, we're walking on air. And the more I was reading and talking to different scientists, the more I was finding out, like, that really happens. There's like a whole chemical basis for it. What happens? What happens in your brain when you get kissed properly? Like a proper romantic kiss by a lover? What happens?

A proper romantic kiss. So we're talking, especially early in a relationship, it's novel. You've been anticipating kissing this person. So there's a spike in a neurotransmitter called dopamine, which you've probably already talked about here and there on the show, I'm guessing. But dopamine is associated with craving and desire. And it's kind of that can't wait to be with someone kind of feeling. Can't wait to see them again. It's that neurotransmit. transmitter that people often hear about in the media because it's associated with certain drugs like cocaine. But, you know, it's not, it's not quite the cocaine effect on your body. But it's just, you really kind of get obsessed because you can't wait to spend time with this person. There's also a change in oxytocin, which we call the love hormone. It's associated with that closeness, that connection. So the right kiss with the right person is going to kind of make you feel like literally closer. We have an uptick in noroprenefarin, so your heart's phrasing, maybe your palms are sweating. The stuff you might feel is a little less appealing, but your partner doesn't

even care at that point. And you see all these different changes. And of course, we do have changes in serotonin. And it can make us feel more relaxed, more at ease, you know, more ready for potentially more. And, you know, that's only the beginning. It's this whole chemical cocktail in our bodies influencing how we feel and what we're thinking about and what we're going to do. And I just, I really love that. It's like a symphony, a chorus of little messengers, deciding how we think we should behave. It's so powerful, isn't it? Like when you describe it like that of what is going on there,

that when I read the book and then I learned that people have tried to ban kissing before, I was like, that's an odd thing to do. But then now, listening to you talk about like what happens in the body, and then now it's kind of making a bit more sense. But tell us who tried to ban kissing. Who's tried that and why? Oh, my goodness. So you can't keep kissing down.

That's the lesson I got through history. So we did see different emperors. I think it was emperor Tiberius. There have been moments when different plagues have run through towns and people kept their distances and different governments or policy folks would say, you know, stay distant, try not to kiss. But we just saw that with the global pandemic when some people became a little more afraid of germs. But we kept kissing each other because that is what we do.

You can't keep kissing down. And it's quite funny. You can find accounts. like Charles Dickens really liked kissing itself, but he didn't like kind of that supplication aspect, the way that people were kissing religious leaders and through history, emperors and things. And so he wrote some very opinionated words

about, you know, why leaders felt that they should be celebrated this way. I mean, it's quite funny, really. But yeah, that was the history piece of this book was probably one of my favorite parts because I'm such a big history nerd. Oh, well, are you in the right place? They bandied you in the place. plague as well. It wasn't just COVID. I completely forgotten about COVID kissing. We just said that. We've just been through a kissing ban. But it happened in the Black Death as well,

didn't it? That was a, I mean, you wouldn't want to kiss someone with the plague anyway. But that was, that was a thing, don't kiss plague people. Well, and it's funny too, because we didn't have germ theory during a lot of these moments when people were saying, oh, don't kiss someone. We didn't know enough about how viruses get transmitted. But we still kind of sense that it must be something with our proximity or with our saliva. But I will say to any listeners who are getting a little squeamish about Kiz, there's a chapter I have in the book called There Are Such Things as Kudis, which I don't know. Cooties is something we say in the U.S. I don't know if you use kudis as much there. We've picked it up from American TV, but do feel free to explain it.

Well, it's just when you think of like two little kids and they don't want to play together, they might say, oh, she has kudies or he has kudies. But despite the fact that, yes, you're exchanging saliva with someone, we are much, more likely to be sick from shaking hands with people throughout our day than all of the kisses that were, well, first of all, how many people are we kissing throughout the day most of the time? We're shaking a lot more hands. We're touching a lot more things. It's not quite as risky a behavior as you would think. And yes, you're exchanging potentially bacteria and stuff, but as long as you're not biting each other, you know, you don't want blood to be. There was a bit of around the time

the book came out, the vampire craze was like off the charts. And so, sometimes especially when I was talking to young people, I'd say try not to bite each other because introducing saliva directly into someone's bloodstream very dangerous, but kissing, not so dangerous most of the time. Well, that's good to know. And I don't know, don't bite anyone listening. I think that's a bad kiss, isn't it? The bitey teeth. Have you ever kissed someone and your teeth touch? That's a bad kiss. Well, at worst with braces, if you're wearing braces or headgear of any kind. Can I ask you, where did the cross for a kiss? come from, that symbol. How old is that and where did that come from? Yeah, I love that story. That's from

the Middle Ages. And there were many men, I mean, men of course were in charge of everything and owned a property and all of this other business. But many men could not read and write. And so for legal contracts, it was acceptable to draw an X and then kiss the X and then it was signed. And so, you know, that was a legal way of leaving a signature and that carried over with the X being the spot that you kissed to the X, the way we use X's with X's and O's today, which is kind of fun. And, you know, we're not usually thinking of like medieval Europe when we're writing XO XO or maybe we are.

No, not often. Anyway, what about kissing as an act of submission? I'm just thinking of what Charles Dickens was saying earlier. He had a lot of stuff to say about everything. But that's true, isn't it? It's used as maybe a marker's respect, but the respect is ultimately you submitting to somebody, right? It's like you kind of, the kiss is being used as a, you know, showing reverence to somebody. Reverence and act of supplication.

Yeah, we have evidence for this thousands of years old. Even in Homer's Iliad, if anyone's familiar with that story. But King Priam kisses, quote, the terrible manslaying hands of Achilles when he is pleading to get his son's body back, Hector. And so we see this over and over. And once again, kings, emperors, all these different people had rules about where on their feet they could be kissed or should their ring be kissed or different things like that. So yeah, it is an active supplication for sure. This is a tricky one. What do you think is the future for kissing? I mean, because it's definitely caught on, hasn't it? Like big time. It's like a really popular pastime now. Yeah. I had a whole

chapter on the future of kissing, which I didn't expect to do it with something that came at the end because my editor had actually asked me that. She's like, well, what's next? You know, the short version is I don't know, but it sure is fun to talk about in research. And, you know, one of the aspects of that is like, we're all talking about artificial intelligence now and AI, but there are companies that have come up with all these different tools and props and machines to try to imitate kissing. There was one that came out of Japan where a couple could sit at opposite ends of the computer and they have this mouthpiece that they kiss that would do the same kind of, I don't know, tongue movements or what have to their partner on the other side of the world or the country. And then there's all these

sex robots that people are trying to invent. So I ended up calling a sex robot engineer. And, you know, I was very nervous because that's not my day-to-day norm calling out engineers thinking about sex robots. And I think he was prepared to answer all sorts of questions. But my question was, you know, well, these robots can do anything, but can they kiss? And then he kind of, he got quiet. He's like, nobody's ever asked me about kissing before. And he thought about it. And he's like, well, they can do a lot of things and they have many orifices, but kissing is not something we've put a lot of technology into. Now, as they mark, especially given that we know that kissing is prioritized more often by women compared to men. And as they start to market more of these, I guess we can call them products to women as well, will they create more functionality around kissing?

And will they ever be able to replicate it? I'm super skeptical because as we've been talking about, kissing is in exchange, we haven't even talked about the aspect of scent, but scent is so important. All of these kind of hidden cues that you can't quite make a robot do no matter how good it is. I don't think you could replicate it, you know, like I mean, you know, like you could have a go at kissing anything. Anyone who's kissed a poster on their wall when they were growing up knows that. But like to actually properly recreate a kiss, you'd have to get body temperature, you'd have to get the smell. And then everything that you've been saying about, a lot of it is intuition and timing. I don't know

if a robot could replicate that, I think it might be a properly unique, you have to have a human there to do that. Yeah, there is a famous experiment that I just love talking about. It's called the sweaty t-shirt experiment. And the scientist, Klaus Wettikind is his name. He had men wear these t-shirts in a certain amount of time where it would start to have their scent,

and then he put them into these boxes with a smelling hole. And then he invited women into his laboratory right, to smell these different t-shirts to talk about what they found most appealing and what they were most repulsed by. And in the end, he found that women were most attracted to the sense of men. They did blood work on all of these people as well. So they found that the women were most attracted to the men who had a different set of genes called the major histo-compatibility complex. It's a set of genes that codes for our immune system. And so the thought is if women are pairing off with men who have a vastly different immune response than they do, their children

potentially could have the best of both worlds and be healthier, more likely to survive, you know, more likely to pass on genes. So it all kind of goes back to evolutionary biology. But if we're attracted to sense for these reasons, well, isn't that neat? That's just going on in the background all the time, this idea of scent and maybe even pheromones, we're not sure. But notably, and this is an important caveat, women who are on the birth control pill showed the opposite preference. They were choosing the sense of men who were most like them. And I just think that's fascinating because clearly, you know, if we're on hormones, we're tricking our bodies into behaving a certain way. You know, we're tricking our bodies into not getting pregnant, of course. But maybe we're fooling ourselves in more ways than we

realize when it comes to selecting a partner. Kind of interesting. Cheryl, that is so interesting. You have been fascinating to talk to. And my final question for you is, what is your favorite movie kiss? What do you think is the best? What's like your favorite kiss in a film? I have an answer for you. It's not a single kiss.

It's a movie of kisses. It's like the last 10 minutes. Have you ever seen Cinema Paradiso? No, I haven't, but I'm going to watch that tonight. It's beautiful. I can't say too much more, but the end is a kissing montage that is just absolutely beautiful. and I think it's impossible to watch without smiling.

I mean, we see other people kissing. It makes us often feel joy and just feel happy. And maybe not everyone, but that's a movie that does that for me. I'm definitely going to watch that tonight. Cheryl, you have been wonderful to talk to. And if people want to know more about you, oh, thank you. If people want to know more about you and your work, where can they find you?

Are you on social media? I am on social media. You can find me everywhere. My website is Cheryl Kirshenbaum.com, but it's a bit of a tricky one to spell. But yeah, Twitter, it's at Cheryl underscore. I'm also on Mastodon, and I'm trying threads, and who knows, but I'm super easy to find. So, yeah, and I'm always interested to hear from readers or folks interested in this at all,

because it's just endlessly fun to chat about. And I really appreciate you having me here to discuss this today, because what a treat for me. You've been so much fun. Thank you for joining me. Thank you. Thank you for listening. And thank you so much to Cheryl for joining me. And if you like what you heard, please don't forget to like, review and subscribe wherever it is that you get to your podcasts.

I know that all podcasters say that and it sounds like such a simple thing, but it really, really does help us if we've got good reviews. And if you want us to explore a subject or if you just fancy dropping by to say hello, please email us at betwixt at historyhit.com. We have got episodes on everything from superstition to dyslexia all coming your way. Join me again, Betwixt the Sheeds, the history of sex scandal and society. a podcast by History Hits. This podcast contains music from Epidemic Sound.